(1) Field of the Invention
The present invention is related to target simulation systems and in particular, to a target simulation system for testing a homing projectile in an underwater environment.
(2) Description of the Prior Art
A typical self-propelled anti-submarine warfare (ASW) torpedo is equipped with electronic homing equipment for enabling the torpedo to seek out its target, such as a submarine. The ASW torpedo can be equipped with a sensitive passive acoustic receiver for detecting sound waves emitted by a target vessel. The received sound waves control the navigation and guidance equipment of the torpedo to direct the torpedo toward the target. The ASW torpedo can also be equipped with an active homing system wherein the torpedo itself generates and transmits an acoustic signal and is guided by the reflection of the acoustic signal off of the target.
The ability of ASW torpedoes to properly home in on and detonate on a target must be tested periodically using exercises known as xe2x80x9cwarshotxe2x80x9d exercises. One type of target currently used for warshot exercises is known as the Mk28, which consists of an acoustic noise maker and a small panel section against which the torpedo detonates. This type of target, however, is an acoustic point source, and most modern ASW torpedoes have sophisticated homing circuitry that does not recognize the Mk28 as a valid target. To accurately test the capability of these modern torpedoes, the torpedoes need to measure the spatial extent of the target and determine the acoustic highlights indicative of the length and construction of the vessel being simulated by the target, such as a submarine. Thus, to test these modern torpedoes with the existing Mk28 target, artificial constraints are placed on the torpedoes being tested, thereby affecting the validity of the testing.
Other types of targets used for testing torpedoes or other homing projectiles are large heavy structures designed to simulate the size and shape of the target vessel. These large and unwieldy targets are difficult to transport and deploy for use during warshot exercises.
One object of the present invention is to effectively simulate a target, such as an underwater vessel, for testing the ability of a torpedo or other homing projectile to home in on and detonate on the target.
Another object of the present invention is a target simulation system that can test the homing and detonation requirements of torpedoes without requiring substantial modification of the torpedo, artificial constraints on the torpedo settings, or other restrictions on the warshot exercise.
A further object of the present invention is a target simulation system having low cost and light weight such that the system can easily be transported and deployed.
The present invention features a target simulation system for testing a homing projectile in an underwater environment. The target simulation system comprises a target simulation portion and one or more suspension assemblies extending from the target simulation portion to a surface of the underwater environment for suspending and supporting the target simulation portion at a predetermined depth within the underwater environment. The target simulation portion includes an impact structure for detonating the homing projectile, and a plurality of reflectors spaced at a distance from the impact structure for reflecting signals transmitted by the homing projectile in a manner that simulates the desired target.
The target simulation portion preferably includes at least first and second boom assemblies extending from the impact structure. The reflectors are disposed in a spaced relationship on one or more booms in the first and second boom assemblies. The first and second boom assemblies preferably include a plurality of booms coupled with flexible couplings.
In one example, the reflectors include passive acoustic reflectors that reflect acoustic signals transmitted by the homing projectile. The target simulation system preferably includes an acoustic noise source disposed on the impact structure for providing a noise simulating the desired target.
The one or more suspension assemblies preferably include first and second boom suspension assemblies, extending from respective ends of the first and second boom assemblies, for suspending the first and the second boom assemblies in the underwater environment. The boom suspension assemblies include a boom support float floating on a surface of the underwater environment, and a boom suspension line extending from the boom support float to a respective one of the boom assemblies.
The target simulation system further includes a reflector sail coupled to the first boom suspension assembly. The reflector sail extends above the surface of the underwater environment and captures surface wind to apply a force that maintains the boom assemblies and the reflectors substantially in line. A drogue is preferably coupled to an end of the second boom assembly for providing a drag force to the target simulation portion such that the reflector sail and drogue apply forces in substantially opposite directions. An additional reflector can be coupled to a float at an end opposite the reflector sail and extend above the surface to reflect radar.
The suspension assemblies further include one or more impact structure suspension assemblies. Each impact structure suspension assembly preferably includes an impact structure support float for floating on a surface of the underwater environment and an impact structure suspension line extending from the impact structure support float to the impact structure.